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Measurements of 18 O/ 16 O ratio are often used to interpret changes in paleoclimate. Oxygen in Earth's air is 99.759% 16 O, 0.037% 17 O and 0.204% 18 O. [13] Water molecules with a lighter isotope are slightly more likely to evaporate and less likely to fall as precipitation, [14] so Earth's freshwater and polar ice have slightly less (0.1981% ...
Oxygen-16 (symbol: 16 O or 16 8 O) is a nuclide. It is a stable isotope of oxygen, with 8 neutrons and 8 protons in its nucleus, and when not ionized, 8 electrons orbiting the nucleus. Oxygen-16 has a mass of 15.994 914 619 56 u. It is the most abundant isotope of oxygen and accounts for 99.757% of oxygen's natural abundance. [2]
Oxygen (chemical symbol O) has three naturally occurring isotopes: 16 O, 17 O, and 18 O, where the 16, 17 and 18 refer to the atomic mass.The most abundant is 16 O, with a small percentage of 18 O and an even smaller percentage of 17 O. Oxygen isotope analysis considers only the ratio of 18 O to 16 O present in a sample.
Oxygen-18 (18 O, Ω [1]) is a natural, stable isotope of oxygen and one of the environmental isotopes. 18 O is an important precursor for the production of fluorodeoxyglucose (FDG) used in positron emission tomography (PET). Generally, in the radiopharmaceutical industry, enriched water (H
In geochemistry, paleoclimatology and paleoceanography δ 18 O or delta-O-18 is a measure of the deviation in ratio of stable isotopes oxygen-18 (18 O) and oxygen-16 (16 O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis.
Emiliani's work in turn depended on Harold Urey's prediction in a paper of 1947 that the ratio between oxygen-18 and oxygen-16 isotopes in calcite, the main chemical component of the shells and other hard parts of a wide range of marine organisms, should vary depending on the prevailing water temperature in which the calcite was formed. [3]
Naturally occurring oxygen is composed of three stable isotopes, 16 O, 17 O, and 18 O, with 16 O being the most abundant (99.762% natural abundance). [60] Most 16 O is synthesized at the end of the helium fusion process in massive stars but some is made in the neon burning process.
Fluorine-18 (18 F, also called radiofluorine) is a fluorine radioisotope which is an important source of positrons. It has a mass of 18.0009380(6) u and its half-life is 109.771(20) minutes. It decays by positron emission 96.7% of the time and electron capture 3.3% of the time. Both modes of decay yield stable oxygen-18.